From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        Kurt Kanzenbach <kurt@linutronix.de>,
        Jacob Keller <jacob.e.keller@intel.com>,
        Gerhard Engleder <gerhard@engleder-embedded.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 net-next 07/15] net/sched: taprio: rename close_time to end_time
Date:   Tue,  7 Feb 2023 15:54:32 +0200
Message-Id: <20230207135440.1482856-8-vladimir.oltean@nxp.com>
In-Reply-To: <20230207135440.1482856-1-vladimir.oltean@nxp.com>
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There is a confusion in terms in taprio which makes what is called
"close_time" to be actually used for 2 things:

1. determining when an entry "closes" such that transmitted skbs are
   never allowed to overrun that time (?!)
2. an aid for determining when to advance and/or restart the schedule
   using the hrtimer

It makes more sense to call this so-called "close_time" "end_time",
because it's not clear at all to me what "closes". Future patches will
hopefully make better use of the term "to close".

This is an absolutely mechanical change.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
---
v1->v2: none

 net/sched/sch_taprio.c | 52 +++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 7d897bbd48ca..3e798c8406ae 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -45,11 +45,11 @@ struct sched_entry {
 	u64 gate_duration[TC_MAX_QUEUE];
 	struct list_head list;
 
-	/* The instant that this entry "closes" and the next one
+	/* The instant that this entry ends and the next one
 	 * should open, the qdisc will make some effort so that no
 	 * packet leaves after this time.
 	 */
-	ktime_t close_time;
+	ktime_t end_time;
 	ktime_t next_txtime;
 	atomic_t budget;
 	int index;
@@ -66,7 +66,7 @@ struct sched_gate_list {
 	struct rcu_head rcu;
 	struct list_head entries;
 	size_t num_entries;
-	ktime_t cycle_close_time;
+	ktime_t cycle_end_time;
 	s64 cycle_time;
 	s64 cycle_time_extension;
 	s64 base_time;
@@ -606,7 +606,7 @@ static struct sk_buff *taprio_dequeue_from_txq(struct Qdisc *sch, int txq,
 	 * guard band ...
 	 */
 	if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
-	    ktime_after(guard, entry->close_time))
+	    ktime_after(guard, entry->end_time))
 		return NULL;
 
 	/* ... and no budget. */
@@ -738,7 +738,7 @@ static bool should_restart_cycle(const struct sched_gate_list *oper,
 	if (list_is_last(&entry->list, &oper->entries))
 		return true;
 
-	if (ktime_compare(entry->close_time, oper->cycle_close_time) == 0)
+	if (ktime_compare(entry->end_time, oper->cycle_end_time) == 0)
 		return true;
 
 	return false;
@@ -746,7 +746,7 @@ static bool should_restart_cycle(const struct sched_gate_list *oper,
 
 static bool should_change_schedules(const struct sched_gate_list *admin,
 				    const struct sched_gate_list *oper,
-				    ktime_t close_time)
+				    ktime_t end_time)
 {
 	ktime_t next_base_time, extension_time;
 
@@ -755,18 +755,18 @@ static bool should_change_schedules(const struct sched_gate_list *admin,
 
 	next_base_time = sched_base_time(admin);
 
-	/* This is the simple case, the close_time would fall after
+	/* This is the simple case, the end_time would fall after
 	 * the next schedule base_time.
 	 */
-	if (ktime_compare(next_base_time, close_time) <= 0)
+	if (ktime_compare(next_base_time, end_time) <= 0)
 		return true;
 
-	/* This is the cycle_time_extension case, if the close_time
+	/* This is the cycle_time_extension case, if the end_time
 	 * plus the amount that can be extended would fall after the
 	 * next schedule base_time, we can extend the current schedule
 	 * for that amount.
 	 */
-	extension_time = ktime_add_ns(close_time, oper->cycle_time_extension);
+	extension_time = ktime_add_ns(end_time, oper->cycle_time_extension);
 
 	/* FIXME: the IEEE 802.1Q-2018 Specification isn't clear about
 	 * how precisely the extension should be made. So after
@@ -785,7 +785,7 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer)
 	struct sched_gate_list *oper, *admin;
 	struct sched_entry *entry, *next;
 	struct Qdisc *sch = q->root;
-	ktime_t close_time;
+	ktime_t end_time;
 
 	spin_lock(&q->current_entry_lock);
 	entry = rcu_dereference_protected(q->current_entry,
@@ -804,41 +804,41 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer)
 	 * entry of all schedules are pre-calculated during the
 	 * schedule initialization.
 	 */
-	if (unlikely(!entry || entry->close_time == oper->base_time)) {
+	if (unlikely(!entry || entry->end_time == oper->base_time)) {
 		next = list_first_entry(&oper->entries, struct sched_entry,
 					list);
-		close_time = next->close_time;
+		end_time = next->end_time;
 		goto first_run;
 	}
 
 	if (should_restart_cycle(oper, entry)) {
 		next = list_first_entry(&oper->entries, struct sched_entry,
 					list);
-		oper->cycle_close_time = ktime_add_ns(oper->cycle_close_time,
-						      oper->cycle_time);
+		oper->cycle_end_time = ktime_add_ns(oper->cycle_end_time,
+						    oper->cycle_time);
 	} else {
 		next = list_next_entry(entry, list);
 	}
 
-	close_time = ktime_add_ns(entry->close_time, next->interval);
-	close_time = min_t(ktime_t, close_time, oper->cycle_close_time);
+	end_time = ktime_add_ns(entry->end_time, next->interval);
+	end_time = min_t(ktime_t, end_time, oper->cycle_end_time);
 
-	if (should_change_schedules(admin, oper, close_time)) {
+	if (should_change_schedules(admin, oper, end_time)) {
 		/* Set things so the next time this runs, the new
 		 * schedule runs.
 		 */
-		close_time = sched_base_time(admin);
+		end_time = sched_base_time(admin);
 		switch_schedules(q, &admin, &oper);
 	}
 
-	next->close_time = close_time;
+	next->end_time = end_time;
 	taprio_set_budget(q, next);
 
 first_run:
 	rcu_assign_pointer(q->current_entry, next);
 	spin_unlock(&q->current_entry_lock);
 
-	hrtimer_set_expires(&q->advance_timer, close_time);
+	hrtimer_set_expires(&q->advance_timer, end_time);
 
 	rcu_read_lock();
 	__netif_schedule(sch);
@@ -1076,8 +1076,8 @@ static int taprio_get_start_time(struct Qdisc *sch,
 	return 0;
 }
 
-static void setup_first_close_time(struct taprio_sched *q,
-				   struct sched_gate_list *sched, ktime_t base)
+static void setup_first_end_time(struct taprio_sched *q,
+				 struct sched_gate_list *sched, ktime_t base)
 {
 	struct sched_entry *first;
 	ktime_t cycle;
@@ -1088,9 +1088,9 @@ static void setup_first_close_time(struct taprio_sched *q,
 	cycle = sched->cycle_time;
 
 	/* FIXME: find a better place to do this */
-	sched->cycle_close_time = ktime_add_ns(base, cycle);
+	sched->cycle_end_time = ktime_add_ns(base, cycle);
 
-	first->close_time = ktime_add_ns(base, first->interval);
+	first->end_time = ktime_add_ns(base, first->interval);
 	taprio_set_budget(q, first);
 	rcu_assign_pointer(q->current_entry, NULL);
 }
@@ -1756,7 +1756,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 		if (admin)
 			call_rcu(&admin->rcu, taprio_free_sched_cb);
 	} else {
-		setup_first_close_time(q, new_admin, start);
+		setup_first_end_time(q, new_admin, start);
 
 		/* Protects against advance_sched() */
 		spin_lock_irqsave(&q->current_entry_lock, flags);
-- 
2.34.1